Gummed labels and the like



Jan. 10, 1967 II GOBEL 3,295,723

GUMMED LABELS AND THE LIKE Filed Jan. 6, 1965 HYDROPHILIC CARBOXYL RESINBARRIER UNDERLYING ENAMEL COATING E 9' If) I 4-PAPER OR POLYVINYLCHLORIDE OR POLYAMIDE BASE 5 HYDROPHILIC CARBOXYL WATER-ACTIVATED GUMREsIN BARRIER UNDERLYING ADHESIVE ADHESIVE GUM HYDROPHILIC CARBOXYLREsIN BARRIER ENAMEL COATING UNDERLYING ENAMEL COATING-\Q 5) (DI-PAPER0R POLYVINYL CHLORIDE 0R POLYAMIDE j BASE X 6L HYDROPHILIC CARBOXYL 3WATER-ACTIVATED GUM RESIN BARRIER UNDERLYING ADHESIVE ADHESIVE GUM 5ENAM EL COATING I 4sPEcIEs OF m x I PLASTIC FOIL I I HYDROPHILICCARBOXYL 3 BQ L'XfQ GUM RESIN BARRIER UNDERLYING ADHESIVE GUM INV TOR.JOHANNES GQBEL IOCQIAMGE "Hay United States Patent 3,296,723 GUMMEDLABELS AND THE LIKE Johannes Gobel, Asch'alfenhurg, Germany, assrgnor toBuntpapierfahrik A.G., Aschafienburg, Germany Filed Jan. 6, 1965, Ser.No. 423,717 Claims priority, application Germany, May 26, 1964, B 76,9283 Claims. (Cl. 40-4) This invention relates to coated paper, and moreparticularly to gummed labels, sheets and sections cut to size, of paperand the like.

The labelling of bottles, cans and boxes, and the paper coverings forcartons, cases and other containers, require a huge amount of labels,sheets and cuttings of ordinary or surface treated paper, such as chromeor cambric paper, which are coated only at the place where they areapplied, by pasting their back With glue of the aqueous or dispersionbase type.

These labels or cuttings suffer from the drawback that when the glue isbeing applied, moisture from the adhesive is apt to pass into the paper,thus causing the label or cuttings to curl, frequently to a point wherethey are applied to the article to be labelled or covered only withdifficulty. Another disadvantage often encountered is a totalpenetration of the glue through the paper which on drying of the glue,leaves glue spots on the surface of the label or covering, so as torender the same unsightly. Another shortcoming frequently observed iscaused by repulsion of the glue by the paper so that the glue covers thepaper unevenly and only in spots, and the label or covering does notadhere properly to the article.

It is a primary object of the present invention to eliminate the abovedrawbacks, and to provide coated labels, sheets, cuttings and the likewhich are materially improved over any gummed paper products nowavailable.

Another important object of the invention is to provide gummed labels orpaper coverings which display no tendency to curl.

It is a further object of the invention to provide labels and similarpaper articles which on application of the glue or adhesive, do notpermit the glue to penetrate the paper so as to detract from a neatappearance of the label.

Still another object of the invention is an adhesive coating for paperlabels and the like which is accepted over the entire surface of thepaper on which it is applied and hence, is bound to ensure adhesion ofthe label or similar paper product on the article to which it isapplied.

It is a still further object of the present invention to provide anadhesive coating which does not tend to peel ofi, and which renders thelabels inert to water, yet wettable, and permeable to vapor.

Other objects, and the manner in which the same are attained, willbecome apparent as this specification proceeds.

The present invention contemplates to provide labels or sheets cut tosize, of papers which may or may not contain Wood and which may have acoated surface, or of plastic foils, and intended to be pasted onarticles by means of glue having an aqueous or a dispersion base, atleast on the side to which the adhesive is to be applied, with a barrierlayer of a carboxyl group containing synthetic or natural resin.

Patented Jan. 10, 1967 "ice A carboxyl group containing synthetic resinpreferred for use in accordance with the invention, is a hydrophilicsynthetic material consisting of carboxyl groups containing polymers,copolymers and mixtures thereof.

Suitable bases for labels and sheets thus pretreated are natural papersas well as all kinds of surface treated papers, such as chromo, gloss,glaze, bright enamel, bronze, plastic, cambric and velvet paper.

In place of paper plastic foils consisting e.g. of polyvinyl chloride,polyamide, cellglass, etc., may be used.

The paper or plastic bases may be coated, in accordance with theinvention,'with hydrophilic synthetic resins and particularly, carboxylgroups containing polyvinyl compounds such as polyacrylic acid, polymethacrylic acid, polymaleic acid anhydride, polycrotonic acid andtheir salts. Copolymers of these compounds with one another, or withother carboxyl group containing vinyl compounds or other compatible andpolymeriza-ble compounds may also be used; suitable examples arecopolymers of the afore-noted compounds with acrylic acid esters,methacrylic acid esters, vinylchloride, vinylidenechloride, vinylacetatevinylalkyl ether, vinylacetal, styrene and the like. Mixtures ofpolymers are as suitable as are copolymers provided the copolymer orpolymeric mixture is susceptible of sweeling in water. With acrylic andmethacrylic acid esters, the lower alkyl esters are preferred.

Hydrophilic natural resins particularly suitable for purposes of theinvention are carboxyl group containing natural resins such as shellac(acid number 40-70) and copal (acid number -190) other resins such asmaleic resin (acid number 120) or carboxyl group containing phthalicresins (acid number -90) are also suitable.

Mixtures of resins are contemplated as are mixtures of resins with thecarboxyl group containing polyvinyl compounds exemplified above.

The barrier layers according to the invention may be applied to the backof an already coated paper, or else they may be applied on both sides ofthe paper or the like base.

The disposition of the barrier layer or layers according to theinvention is illustrated diagrammatically by, the drawing accompanyingthe present specification and forming part thereof, wherein FIG. 1 showsa natural paper which has been coated with the resin compositions of theinvention, on both sides;

FIG; 2 shows a similar paper provided with barrier layers on both sideswhich in addition, has its top surface coated with a chrome or glazecoating, and

FIG. 3 shows a paper having a barrier layer according to the inventionon one side, and a surface improving, chrome or glaze coating on theother side of the paper.

Referring to the drawing, the bases of paper which may or may notcontain wood, or plastic foil, are shown at 1 or 4, respectively, whilethe barrier layers of carboxyl group containing resins are shown at 2and 3, respectively. A surface improving coating intended erg. toenhance the printing characteristics of the paper, is indicated at 5.

Papers or foils provided with barrier layers according to the invention,lend themselves to the manufacture by punching, stamping or cutting, ofsquare, rectangular, circular, oval or irregularly shaped labels,sheets, cuttings and the like. These products have the signal advantagethat they can be pasted by means of a glue or adhesive having an aqueousor dispersion base, on a great variety of articles made of metal, glass,cardboard, plastic, paper, wood, etc., without any tendency to curl orto exhibit stains, and without suffering from uneven or otherwiseimpaired adhesion due to partial repulsion of the glue by the paper. Thewater activated gum adhesive is shown at 6.

The invention is further illustrated by the following examples whereinthe mode of application of the barrier layers according to theinvention, as Well as the chemical characteristics of these coatings,are exemplified with illustrative rather than limitative intent.

Example I 5 kilograms of polyacrylic acid are suspended in 95 liters ofwater, whereupon 3 liters of ammonia, in a 25 percent concentration, arestirred into the suspension. The solution thus obtained is applied bymeans of a coating machine using rollers, the back of the chromo paper,the amount thus applied, calculated on dry substance, being grams persquare meter. Once the coat thus applied has dried, it is sprayed forhardening purposes, with a very thin coat of a 5 percent aqueoussolution of aluminum sulfate, and this, too, is dried.

Drying of the synthetic resin coat takes place in a hanging room.

Polymethacrylic acidmay be replaced by a copolymer of 90 percent ofmethacrylic acid and 10 percent of vinylacetate, with equallysatisfactory results.

Example II 18 kilograms of a copolymer of 35 percent methacrylic acidand 65 percent methacrylic acid methylester are dissolved in a solventmixture composed of 61.5 kilograms of ethyl glycol and 20.5 kilograms oftetraline. Into this solution are stirred 35.7 kilograms of a 70 percentsolution of polyvinylmethylether (K value 40) in toluene. This solutionis applied with a doctor, to the back of a sheet of cambric paper, theamount thus applied being 12 grams per square meter calculated on thedry substance. The solvent is evaporated by placing the coated paper ina drying chamber. The coated paper had all the advantageouscharacterisics noted above.

Example III The solution of Example II is applied with a doctor, to aplastic foil of polyvinylchloride having a thickness of 4Qu. The amountthus applied is 8 grams per square meter, calculated on the drysubstance. As in the preceding examples the solvent is then evaporatedby drying the coated foil in the drying channel.

The coated foil exhibited the superior properties noted above.

Example IV 20 kilograms of polyac-rylic acid are dissolved in a mixtureof 40 kilograms of ethanol and 40 kilograms of methanol. This solutionis applied to the back of a web of glaze paper in an amount of 12 gramsper square meter calculated on the dry substance. The solvent isevaporated as in the preceding examples.

The glazed paper exhibited the outstanding no-stain, non-curling,even-adhesion characteristics of all paper etc. products coated inaccordance with the invention.

Example V A copolymer of male-ic acid anhydride, vinyl acetate and vinylchloride is dissolved in a mixture composed of equal parts of ethylacetate and butyl acetate. The solution is applied with a doctor, to theback of a web of bright enamel paper, in an amount of 10 grams persquare meter, calculated on dry substance. The solvent is evaporated bydrying in a drying chamber, and the resulting coated paper is found tohave all the advantages enumerated e.g. in the preceding example.

4 Example VI A solution of 15 kilograms of a carboxyl group containingpolymethacrylate known under the trade name Plexigum 7613, in 35kilograms of glycolic acid butylester and 7 kilograms of tetraline, isapplied to the back of a web of velvet paper, in an amount of 15 gramsper square meter calculated on the dry substance. The solvent isevaporated by drying in a drying chamber. The resulting productexhibited the same superior characteristics as did the products in thepreceding examples.

Example XII 50 kilograms of China clay, to which 0.5 kilogram of apigment dispersing agent (such as that available on the market under thetrade .name Polysalz) have been added, are mixed with 50 liters ofwater. The paste thus obtained is combined with 183.5 kilograms of ashellac solution composed as follows:

30 kilograms of bleached shellac 150 liters of water 0.5 kilogram ofsoda ash 3 liters of ammonia The resulting mixture is heated understirring, to 60 C.

The coating composition thus obtained is applied by an air brush to theback of a web of paper, the front of which is coated with a chromocoating. It could also be applied to both front and back of a paper web,right in the paper machine, by means of a suitable coating device. Theamount of coating composition applied is 5 grams per square metercalculated on the dry substance, for each side of the web thus treated.

Rectangular labels are punched from a paper web thus treated, whichdisplay all the non-curling, no stain, even adhesion features of theproducts made in accordance with the preceding examples.

Example VIII kilograms of a carboxyl group containing maleic resinavailable on the market under the trade name of Alresat 400 C aredissolved in 40 liters of 96 percent alcohol and 20 liters of xylene.This solution is applied by means of a doctor coating device, to bothsides of a paper web, in an amount of 8 grams per square metercalculated on dry substance, for each side of the Web. One side onlycould be coated as well, and Alresat 444 C could be substituted forAlresat 400 C." The resulting products share all the advantagesenumerated above for the products produced in accordance with thepreceding examples.

I wish it to be understood that I do not desire to be limited to theexact details of procedure, composition and mode of application shownand described as modifications within the scope of the appended claimswhich involve no departure from the spirit of the invention nor anysacrifice of the advantages thereof, will occur to workers in thisfield.

I claim:

1. Gummed labels adapted to be adhered to bottles, cans and boxesthrough adherence of the moistened gum coating comprising incombination, a base selected from the class consisting of paper andpolyvinyl chloride and polyamide, a barrier layer of a carboxyl groupcontaining hyd-rophilic resin on one side of said base, said hydrophilicresin selected from the class consisting of polyacrylic acid,polymethacrylic acid, polymaleic anhydride, polycrotonic acid, acrylicester-acrylic acid copolymer, acrylic ester-methacrylic acid copolymer,methacrylic ester-acrylic acid copolymer, methacrylic ester-methacrylicacid copolymer, vinyl chloride-acrylic acid copolymer, vinylidenechloride-acrylic acid copolymer, Vinyl chloride-methacrylic acidcopolymer, vinylidene chloridemethacrylic acid copolymer, vinylacetal-acrylic acid copolymer, styrene-acrylic acid copolymer,styrene-methacry'lic acid copolymer, shellac of acid 4070, copal of andsaid surface improving enamel coat is provided in the acid 65-190, saidhydrophilic resin barrier layer being other one of said barrier layers.tightly adhesive to the gum applied thereto which has an aqueousdispersion base and further resisting the penetra- References Cited ythe Examiner tion of the gum through itself to the base, and a coat of 5UNITED STATES P ATENTS moisture activated gum adhesive on said barrierlayer.

2. Gummed labels according to claim 1, comprising a 2346624 4/1944Strauss 117*76 X surface improvin enamel coat on the other side of said2458166 1/1949 Homeyer 11776 X D 3,076,588 2/1963 Conway 117-76 X basewhich is opposite said barrier layer and which adapts the label to beprinted. 10 3. Gumrned labels according to claim 2, wherein said EUGENECAPOZIO f barrier layer is provided on both sides of the base with J.CONTRERAS, Assistant Examine!- said coat of adhesive being on one ofsaid barrier layers,

1. GUMMED LABLES ADAPTED TO BE ADHERED TO BOTTLES, CANS AND BOXESTHROUGH ADHERENCE OF THE MOISTENED GUM COATING COMPRISING INCOMBINATION, A BASE SELECTED FROM THE CLASS CONSISTING OF PAPERPOLYVINYL CHLORIDE AND POLYAMIDE, A BARRIER LAYER OF A CARBOXYL GROUPCONTAINING HYDROPHILIC RESIN ON ONE SIDE OF SAID BASE, SAID HYDROPHILICRESIN SELECTED FROM THE CLASS CONSISTING OF POLYACRYLIC ACID,POLYMETHCRYLIC ACID, POLYMALEIC ANYHDRIDE, POLYCROTONIC ACID, ACRYLICESTER-ACRYLIC ACID COPOLYMER, ACRYLIC ESTER-METHACRYLIC ACID COPOLYMER,METHACRYLIC ESTER-ACRYLIC ACID COPOLYMER, METHACRYLIC ESTER-METHACRYLICACID COPOLYMER, VINYL CHLORIDE-ACRYLIC ACID COPOLYMER, VINYLIDENECHLORIDE-ACRYLIC ACID COPOLYMER, VINYL CHLORIDE-METHACRYLIC ACIDCOPOLYMER, VINYLIDENE CHLORIDEMETHACRYLIC ACID COPOLYMER, VINYLACETAL-ACRYLIC ACID COPOLYMER, STYRENE-ACRYLIC ACID COPOLYMER,STYRENE-METHACRYLIC ACID COPOLYMER, SHELLAC OF ACID 40-70, COPAL OF ACID65-190, SAID HYDROPHILIC RESIN BARRIER LAYER BEING TIGHTLY ADHESIVE TOTHE GUM APPLIED THERETO WHICH HAS AN AQUEOUS DISPERSION BASE AND FURTHERRESISTING THE PENETRATION OF THE GUM THROUGH ITSELF TO THE BASE, AND ACOAT OF MOISTURE ACTIVATED GUM ADHESIVE ON SAID BARRIER LAYER.